A relevant example of a method for applying a security code to an article is used in the production of the so-called Europass. For this pass the diffraction-generating microstructure consists of a hologram and the cut-out symbols consist of four numerals, which extend through the entire depth of the hologram. As a result of the cut-out symbols, all that is seen at these locations is the substrate, that is to say the plastic card, which has been burned black. The possibility of the cut-out symbols being rendered invisible by filling up and of new, different personification or identification symbols being cut out is not excluded. Counterfeiting is thus possible.
The aim of the invention is, if not to preclude counterfeiting, certainly to make this appreciably more difficult.